public class Test4 {
    private static int count = 0;
    public static void main(String[] args) throws InterruptedException {
        Object object = new Object();
        Thread t1 = new Thread(() -> {
            for(int i = 0; i < 10000; i++){
                synchronized (object){
                    count++;
                }
            }
        });

        Thread t2 = new Thread(() -> {
            for(int i = 0; i < 10000; i++){
                synchronized (object){
                    count++;
                }
            }
        });

        t1.start();
        t2.start();

        t1.join();
        t2.join();

        System.out.println("count: " + count);
    }
}
